1. Field of the Invention
The present invention relates to a diamond semiconductor device which is formed as a diode, a transistor, or other semiconductor devices using various conduction type dopant doped diamond as a semiconductor material.
2. Related Background Art
Semiconductor devices which operate stably under high temperature, high radiation or other environment, and semiconductor devices which can operate with high powered output have been expected. As a material for such semiconductor devices, diamond has been drawing attention.
Diamond is doped with III-element or V-element, which results in p-type semiconductor or n-type semiconductor, respectively. Further, diamond has a large energy gap of about 5.5 eV, which means that an intrinsic region, at which carrier movement is uncontrollable, is not present below 1400.degree. C. Therefore, with use of diamond as semiconductor, a semiconductor device which is stable thermally, that is, a semiconductor device which can operate at high temperature may be formed.
Diamond is stable chemically and has a heat conductivity of 20 W/cm.multidot.K which is ten times larger than that of silicon and is superior in heat radiation. Further, diamond has a small permitivity of 5.5, a large breakdown voltage of 5.times.10.sup.6 V/cm and a large carrier mobility; an electron mobility of 2000 cm.sup.2 /V.multidot.s and a hole mobility of 2100 cm.sup.2 /V.multidot.s at 300K. Therefore, the diamond semiconductor is also expected to be used at high frequency and high output power.
The techniques relating to such a diamond semiconductor and a diamond semiconductor device are described fully in "Japanese Patent Laid-Open No. SHO 59-208821 (208821/1984)", "Japanese Patent Laid-Open No. SHO 59-213126 (213126/1984)", and "Japanese Patent Laid-Open No. SHO 62-70295 (70295/1987)".